Effect of different concentrations of tert-butylhydroquinone (TBHQ) on microbial growth and chemical stability of soybean biodiesel during simulated storage. (15th November 2016)

• Record Type: Journal Article
• Authors: Beker, Sabrina Anderson; da Silva, Yara Patricia; Bücker, Francielle; Cazarolli, Juciana Clarice; de Quadros, Patrícia Dörr; Peralba, Maria do Carmo Ruaro; Piatnicki, Clarisse Maria Sartori; Bento, Fátima Menezes
• Is Part Of: Fuel. Volume 184(2016)
• Page Start: 701
• Page End: 707
• Publication Date: 2016-11-15
• Subjects: Biodiesel -- Antioxidants -- Biomass -- Oxidation stability -- Water content; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2016.07.067
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: First study on the effect of TBHQ on microbial growth in biodiesel. BHT did not present antimicrobial activity in the culture media. TBHQ appears to be neither promoter nor inhibitor of microbial growth in biodiesel under the conditions tested. Acid number and water content of biodiesel samples were out of specification for commercialization after 45 days of storage. Abstract: Biodiesel's susceptibility to oxidation and its hygroscopic characteristics can cause chemical oxidation and microbial growth during storage, leading to fuel biodeterioration. Although a wide variety of commercial antioxidants have been used to prevent biodiesel oxidation, little is known about the effects of these agents on microbial community. The minimum inhibitory concentration (MIC) of tert -butylhidroquinone (TBHQ) and butylated hydroxytoluene (BHT) against microorganisms isolated from fuel storage tanks was investigated, and only TBHQ presented antimicrobial activity. In laboratory scale, microcosm experiments with soybean biodiesel and different TBHQ concentrations (0; 50; 100; 200; 300; and 600 ppm) incubated for 45 days at 30 °C were performed. The microbial biomass formed at the oil-water interfaces was weighted, and DNA was isolated for DGGE analysis of 16S gene. The quality of commercial biodiesel was investigated by determining oxidation stability, acid number, viscosity, water content, and ester degradation. The results showed higher oxidation stability for the samples containing 100, 300, and 600 ppm TBHQ. The highest biomass formation occurred at TBHQ concentrations of 0, 300, and 600 ppm. The highest microbial diversity was observed in both the commercial samples and those containing 100 and 200 ppm TBHQ. The addition of antioxidant to the microcosms neither inhibited nor enhanced biomass production. An increase in viscosity, acid number, and water content was observed, thus the biodiesel was out of specification for commercialization. Degradation of C16, C18, C18:1, C18:2, and C18:3 esters was not observed in all samples.